Storage battery.



UNITED STATES PATENT OF -Ion.

THOMAS A. EDISON, OF I'LEWELLY N PARK.

WEST ORANGE, NEW JERSEY, ASSIGNOB TO EDISON STORAGE BATTERY COMPANY, OF WEST ORANGE, NEW JERSEY, A COD- PORATION OF NEW JERSEY.

sTonAen BATTERY.

1,083,356. No Drawing.

Specification of Letters Patent.

Application filed April 8, 1911. Serial No. 619,673.

of Llewellyn Park, West Orange, in thecounty of Essex and State of New Jersey, have invented certain new and useful Improvements in Storage Batteries, of which the following is a specification.

The object of my invention is to provide an active material for use in the positive electrodes of alkaline storage batteries, which shall have a reater capacity to store oxygen than the mic el hydroxid ordinarily used in such electrodes. I have found that such a material isobtained by intimately mixin from 1. to 3 per cent. of cobalt hydroxi with mckel hydroxid. This small percentage of cobalt hydroxid raises the capacity of the nickel hydroxid mixture to a substantially higher capacity than without the cobalt hydroxid. The reason for this result has not yet been ascertained, but it is 'probable'that the cobalt hydroxid acts catalytically or in some way alters the hysical structure. I have also found t at the mixture of nickel and cobalt hydroxids possesses particularly advantageous properties as an active material for use in alkaline storage batteries when made by my improved process.

In order to prepare the active material, consisting of nickel hydroxid and cobalt hydroxid I proceed substantially as follows ':T- e proper amount of cobalt sulfate is added to a nickel sulfate solution to obtain the right percentage, the solution being standardized to a known strength; This solution is then slowly added to a standardized solution of sodium hydroxid, while being stirred or otherwise agitated, so that when the reaction is complete there is presout a considerable percentage of free sodium hydroxid, preferably from 10% to 12%. The precipitated pulp is then dried slowly together with a part or all of the soluble products of the reaction and the excess alkali. In this particular case, the principal soluble reaction product is sodium sul fate. The drying is accomplished by first evaporating practically all of the solution water until the precipitated pulp, together with the soluble reaction products and the .excess .alkali, form a cream-like mixture.

This cream-like mixture is then dried very slowly. The d1 ing of the creaml1ke mixture may lie carried on in partlally closed vessels in order that the drymg may be exceedingly slow. The drymg may be carried on more rapidly, but I have found that slow dryin is essential to the best results. Apparent y, some advan-' tageous change in the physical structure of the product is produced by the slow drying 1n.the presence of the stron alkali. The dried material which is easi y broken' into granular form is then washed in a percolator with water, until only a-trace of sulfate or alkali remains. The residue is then drled, and after being crushed and screened n order to obtain a material of roper size, 1s ready for use in the positive eliactrodes of alkaline storage batteries. Other soluble salts of nickel and cobalt, or a mixture of such salts may be em loyed instead-of the sulfate, and other so uble hydroxids or a mixture of such hydroxids instead of sod1um hydroxid. The use of a considerable excess of alkali ,over what is generally used in such precipitations in the precipitation of the nickel and cobalt hydroxids renders the final product more efiicient as an active materlal in the positive electrodes of alkaline storage batteries and the mixture has an increased capacity to store oxygen over the nickel hydroxid made without cobalt. This may be due to porosity or other changes in physical structure brought about by the cobalt, or to some catalytic action-of the cobalt. The degree of porosity or other changes in structure of the final product may be controlled by varying the percentage Patented Jan. 6, 1914.

of excess alkali, Which during the longv suflicient where the nickel hydroxid is used 105 without the cobalt hydroxid.

ndU 2. The process of manufacturing active material for the positive electrodes of alkaline storage batteries, which consists in recipitating a mixture of nickel and co alt hydroxids from a solution of salts of nickel and cobalt, drying the precipitated pulp together with a portion or all of the reaction product or products, washing out the soluble reaction product or products, and finally drying the residue, substantially as described.

3. The process of manufacturing active material for the positive electrodes of alkaline storage batteries, which consists in adding a predetermined considerable excess of alkali over the amount necessary to effect complete precipitation to a solution of a salt of nickel containing a small percentage of a salt of cobalt, drying the precipitated pulp together with a portion or all of the soluble reaction product or products and excess alkali, washing out the excess alkali and the soluble reaction product or products, and finally drying the residue, substantially as described.

- 4. The process of manufacturing active material for the positive electrodes of alkaline storage batteries, which consists in adding from 2 to 12% excess of alkali over the amount necessary to effect complete recipitation to a solution of a salt of nic el containing a small percentage of a salt of cobalt, drying the precipitated pulp together with a portion or all of the soluble reaction product or productsand excess alkali, washing out the excess alkali and the soluble reaction product or roducts, and finally drying the residue, su stantially as described.

5. An active material for the positive electrodes of alkaline storage batteries, consisting of nickel hydroxid containing not more than 5% of cobalt hydroxid, substantially as described.

6. An active material for the positive electrodes of alkaline storage batteries consisting of nickel hydroxid containing a small percentage of cobalt hydroxid made by recipitation with a considerable excess 0 alkali, and dried exceedingly slowly in the presence of the soluble reaction product or products and the excess alkali, substantially as. described.

7. An active material for the positive electrodes of alkaline storage batteries, consisting of nickel hydroxid in porous condition and containing a small percentage of cobalt hydroxid, substantially as described.

This specification signed and witnessed this 7th day of April 1911.

THOS. A. EDI SON.

Witnesses HENRY LANAHAN, ANNA R. KLEHM. 

